The invention relates to a process for the mass conservation of archives by melting a binder combination, which is reinforced by a nonwoven or woven fabric preferably onto both sides.
Recently, because of the alarming news from all libraries and archives, strenuous efforts have been made to rescue printed and written works, which are faced with disintegration and are threatened by wear through use and especially by the time-limited durability of the paper.
The cause of the slight durability of especially modern papers are sulfuric acid and acid-forming components, which have been used in the industrial production of paper since 1850. Unfavorable storage conditions, such as heat, high humidity and climatic fluctuations accelerate the disintegration.
To maintain especially these archives with papers from the period since 1850, a series of chemical methods have been proposed, which consists essentially of exposing the archives to a gaseous or also a liquid neutralizing medium, in order to prevent further destruction by neutralization of the acid constituents of the paper. Admittedly, the further disintegration of the paper can be prevented by such methods; however, the earlier, satisfactory nature of the paper cannot be restored. In particular, the brittleness of the paper, once it has set in, still remains even after such a neutralization. In any case, extensive technical equipment is required for the de-acidification. Such equipment can only be built at a central location and operated by specially trained personnel, so that the archives have to be transported to such a central location for treatment. As a result, the danger of damage to the brittle archives during transport is increased quite appreciably. Moreover, this method is also very expensive and, as already stated, does not help at all in those cases, in which the disintegration of the paper has progressed to such an extent, that use of the neutralized and de-acidified paper is in any case no longer possible for no other reason than because of the brittleness that has developed.
Moreover, a strengthening of paper, which has become brittle due to acid deterioration, has, of course also been attempted. Until now, however, only manual methods are available for this, but no methods that are suitable for mass preservation.
At the present time, the strengthening is carried out manually by using polyethylene film as an adhesive layer in conjunction with nonwoven fabric at a relatively long pressing time (5 to 6 minutes) and at relatively high temperature (120.degree. C.). The result is anything but optimum. The typography is blurred and the high pressing temperature in conjunction with the, after all, relatively long pressing time strongly affects the archive material that is to be restored.